Meh, Spock Prime is a repeat offender then for this sort of thing: Kirk, McCoy, Valeris. All three were melded with without consent.

In short: another case of "Oh, Spock Prime had to do it to <inset plot contrivance>". "Nu Spock broke Vulcan law (which we really don't know if he did or didn't, but but...uh fuck Abrams!"

Let's ignore this 'plot inconsistency- let's blame JJ Abrams' thing.

In each and every case of Prime Spock performing mind melds it was either to save the day, find important information or help his friends overcome mental afflictions (I'm thinking of The Return of the Archons). He had a task to perform and he may have broken his race's code of conduct for mind melds, I don't know, but it served a function.

In fact I think the only questionable use of Prime Spock mind melding was transfering his katra to McCoy. That's more than wacky, that's messed up- moving your soul to a host! However McCoy was a friend of Spock's so that somewhat mitigates it.

Nu Spock had no valid reason for mind melding with Pike, save for vain curiosity.

* Spock wipes Kirk's memory of Rayna to save him the pain. That serves no purpose. And come STV we find out that Kirk never wants he pain taken away.

* Spock forces his katra on McCoy. An act that cause side effects that gets McCoy arrested and facing a life time in a mental hospital. And if Kirk hadn't recovered Spock's body? Sorry Bones, see you on visiting day.

* Spock forcibly restrains a struggling Valeris who was refusing to answer questions. at the time there were fans that raged that that scene was (basically) a rape scene played out in front of the main characters with Kirk demanding information as she screamed out.

In sort: It's a not a damn bit of difference. Oh wait..yes there is: it's in an Abrams movie.